Columns are blackened with soot and vaults have crumbled in one of the courtyards of Syria's the Krak des Chevaliers, a Crusader castle that is a UNESCOWorld Heritage Site and victim of the country's three-year civil war.

The army seized the medieval fortress on Thursday after fierce fighting in the nearby village of Al-Hosn in central Syria, routing rebels who had captured it in July 2011.

Journalists, including an AFP reporter, toured there on Friday on a visit organised by the army.

Most of the fortress, first occupied in the 11th century, and its external walls appear intact but the damage is inside, in the lower courtyard. Fires, apparently set by the rebels who were entrenched inside the fortress, have ravaged ancient pillars, while some archways and vaults have collapsed. Huge blocs of grey stone litter the ground but it is not clear if the damage was caused during Thursday's capture of the fortress or in earlier bombardments.

The only bullet holes that can be seen are on a metal plate that once was inscribed with information for tourists who visited the Krak des Chevaliers, or Fortress of the Knights.

"We acted in a way to preserve the Krak, to make sure it would not be damaged," said a colonel who escorted the journalists on their tour.

In July 2011, four months after the Syrian conflict erupted, Sunni villagers from the village of Al-Hosn seized the Krak and were soon joined by allied rebels, including Lebanese fighters. Islamist fighters also occupied the Krak, including jihadists from Al-Nusra Front, Al-Qaeda's Syria affiliate, and from the Jund al-Sham group.

Leftover food

The fighters were routed after fierce fighting on Thursday, part of an offensive to sever rebel supply lines from neighbouring Lebanon.

They left behind all sorts of supplies. A pot of leftover meat and rice stew can be seen in a room that rebels apparently used as a command centre and living quarters. Rugs cover the hard stone floors, there are cot beds and, on one side of a room that apparently served as the kitchen, there is a cupboard that contains rice and a tin of vegetable shortening. Curtains are strung across loopholes to keep the daylight out and men's clothing is strewn across the room.

Nearby are the women's quarters, said the colonel, adding that 700 rebels lived in the Krak.

The decor is spartan, mattresses on the floor and a small desk, religious books and bottles of henna. Women's clothes can be seen. The room reeks of incense. The rebels even left behind their washing, soaking in the courtyard .

Weapons and mortar rounds are in another room.

In the village of Al-Hosn, the damage is greater. Shop windows are shattered, shards of glass carpet the streets and buildings have been bombarded. Three dead donkeys lie on the side of a road.

The colonel says the army took the rebels by surprise on Thursday and seized the Krak after an operation that lasted 12 hours.

The Krak ranks as one of the best preserved examples of medieval fortresses from the times of the Crusaders, according to UNESCO. Like other Crusader castles in the Middle East, it sits atop a hill that dominates the landscape as far as the eye can see.

Initially Abbassid Muslims built a fortress on the hill in 1031 but the bulk of the existing fortress was built by the Hospitaller Order of Saint John of Jerusalem, which was given the castle in 1142. There were further fortifications built towards the end of the 13th century by the Mamluks, who swept in and seized it from the Crusaders.

The Krak was inscribed on the UNESCO World Heritage Site list in 2006, one of six Syrian sites to get the label.

In 2013, UNESCO decided to add all six of Syria's World Heritage sites to its World Heritage in Danger list, including the Old Cities of Damascus and Aleppo, Palmyra and Qalat Salaheddin fortress. The move reflected growing concern that serious damage was being inflicted on these sites, as the war that erupted in Syria in March 2011 raged on.